Printer technology continues to advance, resulting in commercially available printers having faster speed, increased print quality, and improved features. A wide range of printers are commercially available, ranging from relatively inexpensive “desktop” models with few features to more expensive “printing press” models that have many features and expandable options.
Many printers offer optional accessories that are attached to the output of the printer. One or more of these optional accessory devices may be connected serially to perform various functions, such as binding documents, stapling documents, hole-punching documents, or depositing a document into an appropriate mailbox. When passing documents through certain accessory devices, it is important that the various pages of the document be handled in the proper order. For example, before stapling or binding a document, the document pages must be arranged in the correct order. Many printers generate output in the reverse order (i.e., the first page is printed face-up, the next page is printed face-up and placed on top of the first sheet, and so on).
One technique to reverse the order of multiple printed pages is referred to as electronic flipping. For a printer that prints on one side of the paper (referred to as simplex printing), the printer receives and processes the entire print job internally, and then prints the pages in reverse order (i.e., prints the last page first, then the next-to-the-last page, and so on). This technique requires that the printer have enough memory to receive and process the entire print job prior to printing the first page of the print job. This technique typically slows the printing operation because the entire document must be processed before printing any pages. Further, this technique becomes more complicated when the print job is printed on both sides of the paper (referred to as duplex printing). When printing on both sides of the paper, the printer cannot merely reverse the order of the print job. The printer may need to modify the order in which the page faces are printed because the printer assumes that it will output the pages through an output that performs a mechanical flipping operation. Additionally, the printer may need to insert blank pages (or blank page faces) when printing an odd number of pages.
Some applications are capable of generating print jobs in an inverted manner. If an application supports this type of processing, it generally takes a considerable amount of time to generate the print job. Further, many applications are not capable of generating this type of inverted print job.
Another system to reverse the order of multiple printed pages is referred to as a mechanical flipper. A mechanical flipper physically receives an entire sheet of paper and mechanically flips the paper, then provides the flipped sheet of paper to the output. A problem with this system is the requirement of a dedicated mechanical device to flip each sheet of paper, which represents additional cost and complexity, extra power consumption, and increased printer noise.
The invention described herein addresses these and other problems using an improved system for reversing the order of document pages.